Valve actuating mechanism



my 7 ll H. c. EDWARDS M101 VALVE ACTUTINGA MECHANISM Filed OC'. l0, 1931 13' 16 gmx/nto@ JS/'EHEEHTLL'EDNAHDE E5' E Patented July 7, 1936 Y' Y UNITED STAT-Es PATENT oFFicE VALVE ACTUATING MEcHANisM Herbert C. Edwards, Detroit, Mich., assigner to Packard Motor Car Company, Detroit, Mich., a corporation of Michigan Applittttimn october 1o, 1931, serial No. 568,193 '6 claims. (c1. 12a-90) This invention relates to valve actuating Figure 2 is a corresponding view in which the mechanism and is particularly concerned with parts occupy a different position; and the actuation of poppet valves and the like which Figure is a section on the line 3-3 of Figare Yconstrained to movein a straight line. ure 2.

It is an object of `the invention to provide Referringnow more specifically to the draw- 5 means having rolling engagement with the valve ing, it will be observed that the reference nustem or other element 4movable therewithV for meral IU indicates the stem of a poppet valve actuating the valve whereby sliding engagement of conventional type which is supported for between the `relatively moving parts may be subrectilinear sliding movement in guide apertures stantially eliminated and the resultant wear due I2 formed in a frame I3 which may comprise the 10 to friction avoided. cylinder head of an internal combustion engine,

It is a feature of the invention that in imparta valve box, or other suitable support for the ing movement to the valve ,stem or other elevalve. The head I5 of the valve is arranged to ment constrained to rectilinear motion, the prinengage a Valve seat i6 formed in the frame to ciple of hypocycloidal action in which the d iclose the passage I'I for preventing iiow of fluid 15 ameter of the rolling circle is one half that of therein. A suitable spring Il acting between the fixed circle within which it rolls is emthe frame I3and the collar I4 which constitutes ployed, since the locus of a point on the rolling an abutment on the valve stem urges the valve circle is a straight line. Thus, by providing a normally to closed position.

fixed surface having a givenradius of curvature A rocking element 20 provided with a valve 20 and an element having an arcuate portion of engaging portion 2| adjacent one end thereof half that radius rolling onthe fixed surface, any and a seat 23 for engagement with a push rod I point on the rolling element lying` on its curved 24 adjacent the other end thereof serves to thrust g surface or an extension thereofrwill execute linear the valve stem downwardly as shown in Figure L25 movement and may thus be employed to Vimpart l todisplace the valve head I5 from the seat I6 25 substantially linear movement to the valve stem Ain the conventional manner. The member 2U or associated elements. is -arranged to rock in engagement with a fixed It is a more specific object of the invention member 26, the latter being secured to any conto provide means for engaging and actuating a venient portion of the frame by bolts or rivets poppet Valve comprising an element provided 21. It will be understood that in the applica- 30 with a curved surface, or the equivalent thereof, tion of this invention to the actuation of valves arranged to rock on a second fixed curved surfor internal combustion engines, the fixed memface, the radius of curvature of the fixed curved ber 26 may be secured to the cylinder head or the surface being substantially twice that of the rocker box associated therewith.

` curved surface formed on the rocking element, In the embodiment of the invention shown in 35 the rocking element being provided with a furthe drawing, the members 20 and 26 are illusther valve stem engaging surface having a relatrated as provided with cooperating toothed surtively slight radius of curvature, the center of faces numbered 28 and 29, respectively. The which is located on an extension of its first center of the pitch circle of the toothed surface 40 named Curved Surface-A By proper selection 0f 28 isindicated at 30 and the center of the pitch 40 the radii 0f the Several Curved Surfaces .and the time for the toothed surface 29 is` indicated at relative disposition of the several elements with 32 it being noted that the radii of these pitch respect t0 the path of movement of the Valve circles are inthe ratio of l to 2. Thus, when Stem the rocking @ement may engage me Valve the push rod 24 is moved upwardly from the postem with substantially pure rolling action and Simon which it occupies in Figure 1 of the drawn 45 side thrust on the stein as well as wear due to v ing, the member 20 will rock on the fixed memfriction between `the engaged parts can be elimiber 26 and the Valve m Wm be depressed to Sub nated. i

Further objects and features of theinvention Stant-1a11y the posltlon shown m Flgure 2 of the will be apparent from the vfollowing specification drawug' taken in Connection with the,` accompanying It will be appreciated that the coacting memdrawing, in which: bers 20 and 26 need not be provided with teeth, Figure 1 is aview partlyin section iilustratthe provision of arcuate engaging Surfaces on ing the application of the principles of the inventhese members having their radii. of curvature tion to the actuating of a poppet valve; corresponding with the radii of their pitch circles 55 as shown in the drawing serving to actuate the valve stem in the manner intended.

Referring now to the valve engaging portion 2| of the member 2U, it will be observed that this portion comprises a substantially cylindrical surface in direct engagement with the valve stem l0, the axis or center of this surface being located at 34 on an extension of the pitch -circle of the toothed portion 28 of the member 2D. The radius of this cylindrical surface is so chosen that as the valve is depressed to open the passage I1 the locus of the point of engagement between the portion 2| on the member 20 and `the stem is approximately a line connecting the points 34 and 32, it being appreciated that the rolling nature of the engagement between the member 20 and the valve stem I will result in a gradual shifting of the point of contact to the left as the valve stem is depressed.

By reason of the fact that the axis 34 is located substantially on an extension of the pitch circle of the toothed portion 28 of the member 20, this axis 34 corresponds to a point on a circle rolling within a fixed circle, the radius of the latter being twice that of the former and thus any point on the axis 34 will move in a straight line. In this manner the side thrust on the valve stem is substantially eliminated and approximately pure rolling action is obtained between the member 20 and the valve stem at their point of engagement.

For convenience, it may be necessary to support the rocker 2!! so that the push rod may be removed without disturbing the remaining elements. This support may consist of a bracket 35 bolted or riveted at 36 to the frame I3 and provided with flanges 31 extending on either side of the member 20 to prevent lateral shifting of this member. It is, of course, necessary in order to accommodate the slight rocking movement of the member 20 that the main portion of the bracket 35 be spaced from the lower surface 38 of the member 20, a fiat spring 40 secured to the bracket 35 intermediate the iianges 31 and beneath the surface 38 being preferably provided to maintain the toothed surfaces 28 and 29 in engagement in the event the push rod 24 is removed.

It will be understood that the specific arrangement of the valve actuating mechanism described herein is designed to facilitate an understanding of the principles of the invention and that .such 'changes and alterations are contemplated as fall within the spirit and scope of the appended claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. In valve actuating mechanism, the combination with a poppet valve having a stem, of a fixed member having an arcuate portion disposed adjacent and to one side of said valve, said arcuate portion being struck from a center displaced slightly from the center line of they valve stem on the other side thereof, a movable member having an arcuate portion rolling on the arcuate portion of said fixed member and having a radius substantially one-half that of the arcuate portion of the fixed member, and a lcurved surface bearing on the end of the valve stem, the center of said curved surface lying approximately on an extension of the arc defining the arcuate portion of the movable member, said curved surface having a radius of curvature such that when the movable member rolls on the fixed member the locus of the point of contact of said curved surface and valve stem passes approximately through the center from which the arcuate portion of the fixed member is struck.

2. In a mechanical movement, the combination With Ya, movable driven element, of means constraining said driven element to move in a straight line, a fixed arcuate track, and a member having an arcuate portion of one half the radius of said arcuate track adapted to roll on the latter, and an arcuate bearing surface on said member having a. center lying Von an extension of the arc defining said arcua portion for driving engagement with said driven element, the center from which said arcuate track is struck lying approximately in the locus of the point of engagement between said member and said driven element.

3. In a mechanical movement, the combination with a 'movable driven element, of means constraining said element to move in a straight line, a driving element having a lconvexly curved bearing surface engaging said driven element, aiixed element having a concave circular bearing portion, said driving element having a convex circular bearing portion of half the radius of said last named portion rolling thereon, the point of engagement between said driving and driven elements being located closely adjacent the extension of the arc defining the circular bearing portion of said driving element.

4. In valve actuating mechanism, the combination with a poppet valve, of a fixed member having an arcuate portion disposed adjacent and to one side of said valve, a movable member having an arcuate portion adapted to roll on the arcuate portion of said fixed member and having a valve engaging portion, said valve engaging portion being disposed in proximity to an extension of the curve defining the arcuate portion of said movable member, the arcuate portion of said fixed member having a radius substantially twice that of the arcuate portion of said movable member.

5. In a mechanical movement, the combination With a movable driven element, of means constraining said element to move vin a straight line, 'a driving element having a convexly curved bearing surface engaging said driven element, a fixed velement having a concave circular toothed portion, said driving element having a convex circular toothed portion of half the radius of said last named portion rolling thereon, the point of engagement between said driving and driven elements being located closely adjacent the extension of the arc defining the circular toothed portion of said driving element.

6. In valve actuating mechanism, the combination with a poppet valve, of means movable in a straight line and associated with said valve for actuating the same, a fixed member having a curved portion, and means including an element having a curved portion rocking on the curved portion of said member and a curved surface engaging said first named means, the radii of curvature of said portions being substantially in the ratio of 2:1, said curved surface being disposed in close proximity to the extended arc defining the curved portion-of said element, whereby said element 'may engage said means with approximately pure rolling contact with said rst named means for imparting movement to the latter.

HERBERT C. EDWARDS. 

